To organise 5 given metals into a reactivity series using 0.2 M Copper (II) Sulphate Solution.

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Introduction

A SHORT REACTIVITY SERIES Aim: To organise 5 given metals into a reactivity series using 0.2 M Copper (II) Sulphate Solution. Safety: Before we can even begin, utmost precautions must be taken when it comes to safety. We will ensure that all things that aren't absolutely necessary are cleared of the bench and placed underneath it, so as to ensure that no one can trip over them. Shirts will be tucked in to prevent any mishaps, and we will be wearing safety goggles, to prevent anything from getting in our eyes. Throughout the entire investigation we will be standing up, to make sure that if there is any major problem on the bench, we will be in a position to do something about it. We will also have to take precautions when it comes to a metal like calcium. Since it can react with water on skin, we must make sure that it does not come into contact with any part of our body. Plan: To be able to produce our reactivity series, we must make use of the fact that a more reactive metal will displace a less reactive metal from its salt solution. When this happens, heat energy is released as the reaction is an exothermic one. The greater the difference in reactivity between the two metals, the more energy released. This fact allows us to measure the temperature rise and judge from that which metals are the most reactive and which the least. The reactivity series is a table of metals with the most reactive metals at the top of the table and the least reactive metals at the bottom. Since I only have 500cm3 of 0.2 molar Copper (II) Sulphate solution and 5 metals, I have decided to test each metals 4 times using 25cm3 of Copper (II) Sulphate solution each time. This maximises the use of the Copper Sulphate Solution. ...read more.

Middle

For example, if we were testing magnesium, then we would measure out 0.096g of magnesium on the top pan balance and add it to the copper sulphate solution and shake the cup gently, all the while looking reading off the thermometer. Every thirty seconds we will note down the temperature achieved by the metal reacting with copper sulphate solution. We will test each metal for four minutes with 4 attempts. This will allow us to get a good spread of readings. Every time we finish one attempt of a metal, we will wash out and dry the cup and do the experiment again in the same cup. After we have the complete readings for each metal within a table, we will find the maximum temperature achieved from each attempt and put it in a table along with all the other metals. Form here we can then go on to find the maximum temperature rise achieved in each attempt by taking the maximum temperature away from the baseline temperature of the copper sulphate and the take an average maximum rise in temperature for each metal. PREDICITION: I predict that the reactivity series for those 5 metals will look like this: Calcium Magnesium Zinc Iron Copper The reason for my putting copper at the bottom of the reactivity series is obvious. Copper is not likely to react with its own salt solution (Copper (II) Sulphate) From previous experiments, we have seen that when calcium reacts with cold water the reaction can be described as vigorous, fizzing and giving off hydrogen gas. The same can be said for when calcium reacts with dilute acid. It is because of these two facts that I have placed calcium at the top of my reactivity series. Previous investigations have also shown that magnesium will not react with cold water, but it will react with steam to produce magnesium oxide and hydrogen gas. ...read more.

Conclusion

The ionic bond between the magnesium ion and the sulphate group is made. The copper ions must gain electrons and make metallic bonds with each other to become the black solid. These changes give out energy, too. In this reaction, the amount of energy taken in by the bonds being broken is less than the energy given out by the bonds being made. So on balance we see energy being given out as heat. It is an exothermic reaction. Every reaction involves energy changes. In order for a reaction to take place old bonds need to be broken and new bonds need to be formed. This involves energy. To break bonds, energy is needed. This is why many reactions need to be heated to get them started. Those that happen at room temperature are still using the heat from the surroundings to get started, they just don't need as much. The process of breaking bonds is endothermic (needs heat). When bonds are made, energy is released. This is an exothermic reaction (heat is given out). In the reaction you describe, the zinc is more reactive than the copper. As a result, it acts a bit like a bully, demanding that the copper give it the sulphate ions. Energy is needed to break the bonds between the copper ions and the sulphate ions. When the zinc bonds to the sulphate ions, energy is given out. The more zinc that is there, the more 'demanding' it is because every zinc ion wants to bond with a sulphate ion and so they are competing with each other as well as with the copper. A displacement reaction is an example of a redox reaction. In a redox reaction one reactant loses electrons (oxidation) while the other gains the electrons (reduction). For example zinc metal will displace copper ions from solution because zinc is higher than copper in the electrochemical series. Zinc ions and copper atoms (metal) are formed - the zinc atoms lose electrons while the copper ions gain the electrons. Zn � Zn2+ + 2e (oxidation) Cu2+ +2e � Cu (reduction) ...read more.

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Then I would imagine that magnesium would create the next largest reaction and give off heat. Following that will be zinc and then iron. I am predicting this information on the basis of the metals rank in the reactivity series.

It is worked out by adding up the Atomic Number (Ar) of all the elements present in the substance. The molar mass of Potassium Manganate (VII)(s) Potassium Manganate (VII) = 158 The molar mass of Iron (II) Ammonium Sulphate(s) Iron (II)

= 25 = 0.384 moles RMM 65 I will also record the initial and final temperatures of the solution and then re-weigh it. I will then process the results that I obtain by firstly using the formulae M*C* T, which will give me the energy gained by copper sulphate, this is given in joules.

Clean out the micropipette. This is so that the micropipette is clean for each step, so the solutions are not contaminated. For the fourth solution I will add 24ml of the 0.6 mg/l solution with a micropipette to a beaker with 216ml of distilled water and mix.

Calcium is not included above. But from preliminary work done I have learnt that calcium is very reactive and that it is very hard to test the temperature given off in this reaction by using the methord of testing which I am planing to use in this experiment.

It is a reactant in both experiments 0.2M CuSO4 This is added in a suitable volume as a reactant in the first experiment 0.2M Pb(NO3)4 This is added in a suitable volume as a reactant in the second experiment Safety 1.

equation is 4Mg+O2 equals to 2Mg2O.The other reason I think magnesium is more reactive than the other metals apart from calcium is because magnesium reacts more violent than iron, zinc and aluminium in water much faster than them.The word equation for this reaction is Magensium+water equals Magnesium hydroxide+hydrogen gas and